Improving the type signature of `setattr`

When the first argument of setattr is of type NoneType or EllipsisType the function will always raise an AttributeError on runtime, so it would be nice if the following calls would be detected as type errors.

x = None
setattr(x, 'foo', True) # AttributeError: 'NoneType' object has no attribute 'test'
y = ...
setattr(y, 'foo', True) # AttributeError: 'ellipsis' object has no attribute 'test'

I am not sure what's the best way to go about this is, there are probably many builtin types that do not support arbitrary attributes to be set. We do not appear to have a type to categorize such types, which could then in the future be used with Not[], once python/typing#801 is implemented.

Commencez par localiser le stub de typeshed pour le setattr intégré et examinez la discussion associée dans python/typing#801. Déterminez comment la signature doit refuser NoneType et EllipsisType sans exclure incorrectement d’autres cibles valides ; le travail est considéré comme terminé lorsque les appels concernés sont signalés comme des erreurs de typage et que les cas existants de setattr restent pris en charge.